Eco-friendly heat exchange system between water treatment device and external plant

ABSTRACT

Disclosed is a heat exchange system between an external plan such as a data center and a water treatment device of a sewage treatment plant. The present system includes a hot-air supply unit that supplies heat generated from the external plant to a reactor using microorganisms in the water treatment device, and a coolant supply unit that supplies treated water discharged from the water treatment device to the external plant as a coolant for heat dissipation of the external plant. It is possible to simultaneously solve various problems in terms of environmental and economic aspects by enabling complementary heat exchange between the external plant and the sewage treatment plant.

TECHNICAL FIELD

The present invention relates to a heat exchange system for reusingwaste heat by exchanging the waste heat between a water treatment devicein a sewage treatment plant and an external plant such as a data center.

BACKGROUND ART

A water treatment device in a sewage treatment plant refers to anindividual technology or system of the sewage treatment plant thatpurifies and treats contaminated water such as sewage, dirty water, andwastewater. A method of treating sewage may be different depending on atype of pollutant to be removed. However, in general, solids arephysically or chemically removed, and organic matters, nitrogen,phosphorus, and the like are removed by biological treatment withmicroorganisms. For the biological treatment, a reactor for culturingmicroorganisms that survive by feeding on pollutants is required, and atemperature of the reactor is very important for growth and activationof microorganisms. In particular, a decrease in water temperature inwinter causes a problem of lowering biological reaction efficiency bylowering microbial activity. As long as the water temperature does notexceed 40° C., the higher the water temperature, the better thebiological treatment efficiency, which may reduce operating costs suchas energy costs and stably secure effluent quality. If a heat source maybe supplied to the sewage treatment plant at a low cost or free ofcharge, the heat source may increase operational efficiency of abiological reaction and may be used for drying sludge or the like thatis generated during sewage treatment. In this way, the operating costsof the sewage treatment plant may be saved, and carbon emission may bereduced by reducing energy consumption.

On the other hand, there are various industrial plants that generate alarge amount of heat during operation. Conventionally, heat is mainlygenerated in plants that produce chemicals or specific products, butrecently, with the development of the data communication industry, heatgeneration in data centers is becoming a problem. The data center is afacility that is connected to external communication networks such asthe Internet to store data transmitted and received through externalcommunication networks. Not only portal site operators or cloud serviceproviders, but also public institutions are operating large-scale datacenters to store a large amount of data. These data centers arepreferably installed in suburbs of cities in consideration of theconvenience of securing competent working manpower, security, andelectric power, connectivity with the external communication networks,and the like, but are causing many problems, such as difficulty insecuring a site, power shortage due to a large amount of energy requiredto cool the generated heat, global warming, and the occurrence of anurban heat island phenomenon.

DISCLOSURE Technical Problem

As described above, the sewage treatment plant wants to economicallyreceive an appropriate heat source for biological treatment efficiency,economical sludge treatment, or the like, and the external plants suchas the data centers want to overcome carbon emissions, power shortages,and the heat island effect by removing the generated heat. The presentinvention has been devised in view of such circumstances, and is tosimultaneously solve various problems in terms of environmental andeconomic aspects by enabling complementary heat exchange between anexternal plant and a sewage treatment plant.

Technical Solution

The present invention provides a heat exchange system between anexternal plant that generates heat during operation and acts as a heatsource for the surrounding environment and a water treatment device fortreating sewage. According to the present invention, the heat exchangesystem includes a hot-air supply unit that supplies heat generated fromthe external plant to a reactor using microorganisms in the watertreatment device, a coolant supply unit that supplies treated waterdischarged from the water treatment device to the external plant as acoolant for heat dissipation of the external plant, and a control unitthat controls an operation of the hot-air supply unit and the coolantsupply unit.

The external plant may include a data center that transmits and receivesdata through an external communication network and stores the data.

The hot-air supply unit may include a hot-air pipe that provides ahot-air movement path between the reactor and a heat exchanger providedin the external plant, and a blower that blows hot air from the heatexchanger to the reactor through the heat engine.

The hot-air pipe may further provide the hot-air movement path betweenthe heat exchanger and a dryer for drying sludge generated in thereactor, and the blower may blow hot air from the heat exchanger to thedryer through the hot-air pipe.

A valve may be installed on the hot-air movement path of the hot-airpipe to control a supply of the hot air to the reactor and the dryerthrough the hot-air pipe. The control unit may control the valve so thatthe supply of the hot air to the reactor and the dryer is individuallyregulated.

The coolant supply unit may include at least one of a first cooling pipethat supplies the treated water to the heat exchanger provided in theexternal plant, a second cooling pipe that is installed outside theexternal plant or buried in an outer wall of the external plant andsupplied with the treated water, a sprinkler that cools the externalplant by sprinkling the treated water to the outside of the externalplant or supplies water to plants planted in the external plant forbuilding greening, and a sprayer that sprays the treated water tooutside air supplied for cooling the external plant.

The coolant supply unit may further include a pump that supplies thetreated water to at least one of the first cooling pipe, the secondcooling pipe, the sprinkler, and the sprayer.

The coolant supply unit may further include a recovery pipe thatrecovers some or all of the treated water, which is supplied to theexternal plant and used for cooling, to the water treatment device.

The coolant supply unit may further include a storage unit that storesthe treated water to be supplied to the external plant.

The coolant supply unit may further include a circulation pipe thatcirculates some or all of the treated water, which is supplied to theexternal plant and used for cooling, to the storage unit.

The coolant supply unit may further include a cooler that cools thetreated water stored in the storage unit.

The coolant supply unit may further include a fuel cell that generateselectric power to be supplied to the cooler by using biogas generated inthe reactor as a fuel.

Some of the electric power output from the fuel cell may be supplied tothe external plant.

The coolant supply unit may further include a turbine that generateselectric power to be supplied to the cooler by burning the biogasgenerated in the reactor.

Some of the electric power output from the turbine may be supplied tothe external plant.

The heat exchange system may further include a converter that convertscarbon dioxide generated by burning the biogas into ethanol andsupplying the ethanol to the reactor.

When a temperature of the hot air supplied to the reactor through thehot-air supply unit is higher than that required for activation of themicroorganisms in the reactor, the coolant supply unit may supply someor all of the treated water to an outside of the hot-air pipe to coolthe hot air supplied through the hot-air pipe.

The control unit may control an operation of the hot-air supply unit andthe coolant supply unit based on any one of a temperature of the hotair, a temperature of the reactor, a temperature of the external plant,water quality of the treated water, a temperature of the treated water,and a sewage treatment capacity of the water treatment device.

Advantageous Effects

According to the present invention, heat generated in an external plantsuch as a data center that uses a huge cost for cooling is recovered andused for various purposes in a sewage treatment plant. When a coolingmethod of an external plant such as a data center is air cooling, hotair generated from a data center is supplied to a sewage treatment plantand used for sewage treatment or sludge drying. When a method of coolingan external plant is water cooling, treated water from a sewagetreatment plant is used as a coolant supply source to remove heat fromthe external plant. Treated water recovering heat in a data center isused directly as influent of the sewage treatment plant or used to raisea temperature of the sewage treatment plant by allowing a pipe of thetreated water to pass through the influent or a biological reactor ofthe sewage treatment plant.

A complementary heat exchange between an external plant to remove heatand a sewage treatment plant that requires heat helps to solve socialand environmental problems, such as climate change and heat islandcontrol, as well as stable and economical operation of both facilities.Various heat exchange methods described above may be appliedindependently or may be used together.

It is possible to implement an automatic operation that may increaseeconomic efficiency and effectiveness by selectively using variouscooling methods at the same time or individually according tocharacteristics of season or temperature. For efficient and stable heatexchange operation, an AI-based optimal operation system may be applied.An operation system selects an optimal heat exchange method based onreal-time monitoring data such as temperature, humidity, and electricenergy of a data center and a sewage treatment plant, and suggestsstable driving by predicting the amount of heat generated by applying amachine learning algorithm and early warning.

By building a sewage treatment plant underground and building a datacenter on the ground above the sewage treatment plant, it is possible tohave a great effect in solving a site problem of the sewage treatmentplant and the data center and coping with climate change and a heatisland effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a complementary heatexchange situation between a water treatment device and a data center bya heat exchange system according to the present invention.

FIG. 2 is a diagram illustrating a state in which a water treatmentdevice is installed in a way that is buried underground as anotherexample of FIG. 1 .

FIG. 3 is a block diagram illustrating a configuration of a heatexchange system according to the present invention.

FIG. 4 is a block diagram illustrating a state in which the heatexchange system of FIG. 3 is applied to a water treatment device and adata center.

FIG. 5 is a diagram illustrating a state in which a detailedconfiguration of the present invention is additionally provided in theheat exchange system of FIG. 4 .

BEST MODE

Hereinafter, the present disclosure will be described in more detailwith reference to the accompanying drawings.

FIG. 1 is a diagram schematically illustrating a complementary heatexchange situation between a water treatment device and a data center bya heat exchange system according to the present invention.

The present invention exemplifies, as an example of an external plant, adata center 20 that transmits and receives data through an externalcommunication network and stores the data. However, the data center 20is only an example of an external plant to which the heat exchangesystem of the present invention is applied, and the present inventionmay be applied to other industrial facilities, which generate heat andrequire heat dissipation, in addition to the data center 20. That is,the external plant of the present invention includes all kinds offacilities that generate heat during operation and act as a heat sourcefor the surrounding environment. According to the present invention, thewater treatment device 10 is a facility that requires a supply of hotair for activating microorganisms by including a reactor for watertreatment using the microorganisms, and the facility may include afacility for drying sludge generated during sewage treatment, etc.

The heat exchange system according to the present invention implementscomplementary heat exchange between the water treatment device 10 andthe data center 20. The water treatment device 10 and the data center 20are installed at a location adjacent to each other, and the heatexchange system is disposed therebetween or disposed inside the watertreatment device 10 and the data center 20, respectively. The heatexchange system supplies some or all of the hot air generated in thedata center 20 to the water treatment device 10, and the water treatmentdevice 10 supplies some or all of treated water with clean water as aresult of treating sewage to the data center 20. The treated water usedas coolant in the data center 20 is recovered by the water treatmentdevice 10 again, and thus, is used as a heat source of the watertreatment device 10 and at the same time is re-treated by the watertreatment device 10 to be purified with treated water having higherquality water.

FIG. 2 is a diagram illustrating a state in which a water treatmentdevice is installed in a way that is buried underground as anotherexample of FIG. 1 . The present invention may be applied when the watertreatment device 10 and the data center 20 are installed on the groundas illustrated in FIG. 1 , but may also be applied when the watertreatment device 10 is buried underground as illustrated in FIG. 2 . Inthis case, an area of a site required for installing the water treatmentdevice 10 and the data center 20 is reduced, so the present inventionmay be more economically implemented.

FIGS. 3 to 5 are diagrams illustrating a heat exchange system accordingto the present invention. FIG. 3 is a block diagram illustrating aconfiguration of a heat exchange system according to the presentinvention. FIG. 4 is a block diagram illustrating a state in which theheat exchange system of FIG. 3 is applied to the water treatment device10 and the data center 20, and is a diagram mainly illustrating aconfiguration directly related to heat exchange among the configurationsof the heat exchange system of the present invention. FIG. 5 is adiagram illustrating a detailed configuration additionally provided tothe configuration of FIG. 4 so that the heat exchange system of FIG. 4has high heat exchange efficiency and an eco-friendly configuration.

The water treatment device 10 to which the present invention is appliedincludes a reactor 12, a dryer 14, and an advanced treatment device 16.The reactor 12 accommodates microorganisms, and treats incoming sewageby the microorganisms. The treated water treated in the reactor 12 issupplied to the advanced treatment device (16) as needed to besecondarily treated with better quality water. Sludge generated in thereactor 12 is supplied to the dryer 14 and dried in the form of adewatering cake. The dryer 14 supplies hot blast to sludge in order todry the sludge. The heat exchange system of the present invention usesthe treated water discharged from the conventional water treatmentdevice 10 to cool the data center 20.

The data center 20 has a heat exchanger (not shown) therein. The heatexchanger sucks air from the outside of the data center 20 and suppliesthe sucked air to the inside of the data center 20 to cool heatgenerated by the operation of the data center 20, and discharges the hotair, whose temperature has increased by being used for cooling, to theoutside. The heat exchange system of the present invention uses hot airgenerated and discharged by the cooling system of the typical datacenter 20 as a heat source supplied to the water treatment device 10.

The heat exchange system of the present invention includes a hot-airsupply unit 100, a coolant supply unit 200, a converter 300, and acontrol unit 400. The hot-air supply unit 100 serves to supply the hotair generated in the data center 20 to the reactor 12 in the watertreatment device 10, and the coolant supply unit 200 serves to supplythe treated water discharged from the water treatment device 10 to thedata center 20 as a coolant for heat dissipation of the data center 20.As will be described later, the converter 300 serves to convert carbondioxide generated when biogas generated in the reactor 12 is burned intoethanol and supply the ethanol to the reactor 12. The control unit 400serves to control the overall operation of the detailed configuration ofthe heat exchange system of the present invention, including theoperation of the hot-air supply unit 100, the coolant supply unit 200,and the converter 300.

The hot-air supply unit 100 includes a hot-air pipe 110, a blower 120, avalve 130, and a biogas supply pipe 150.

The hot-air pipe 110 provides a hot-air movement path between the heatexchanger in the data center 20 and the reactor 12 in the watertreatment device 10. The hot-air pipe 110 includes a first hot-air pipe111 and a second hot-air pipe 112, which are branched from the hot-airpipe 110 to connect to a reactor 12 and a dryer 14, respectively.Accordingly, the first hot-air pipe 111 provides the hot-air movementpath from the heat exchanger in the data center 20 to the reactor 12,and the second hot-air pipe 112 provides the hot-air movement path fromthe heat exchanger in the data center 20 to the dryer 14.

The blower 120 serves to blow the hot air supplied through the hot-airpipe 110 to the reactor 12 and the dryer 14. In this case, the hot airblown by the blower 120 is supplied to the reactor 12 through the firsthot-air pipe 111 and is supplied to the dryer 14 through the secondhot-air pipe 112.

The valve 130 is installed on the hot-air movement path of the hot-airpipe 110 to control the supply of hot air to the reactor 12 and thedryer 14 through the hot-air pipe 110. The valve 130 is installed at abranch point of the first hot-air pipe 111 and the second hot-air pipe112 in the hot-air movement path of the hot-air pipe 110 or in installedin the first hot-air pipe (111) and the second hot-air pipe (112),respectively, to individually control the supply of hot air to thereactor 12 and the drier 14 through the first hot-air pipe 111 and thesecond hot-air pipe 112. An opening/closing operation of the valve 130is controlled by the control unit 400. As an example, the control unit400 opens the first hot-air pipe 111 to supply hot air into the reactor12 when the temperature in the reactor 12 is 25° C. or lower, and opensthe second hot-air pipe 112 to supply the hot air into the dryer 14 whenthe temperature in the reactor 12 is 35° C. or higher.

The biogas supply pipe 150 provides a path for supplying biogasgenerated during the treatment by microorganisms in the reactor 12 to afuel cell 253 or a turbine 254.

The coolant supply unit 200 includes a first cooling pipe 211, a secondcooling pipe 212, a sprinkler 213, a sprayer 214, a pump 215, a recoverypipe 230, a storage unit 251, a cooler 252, a fuel cell 253, and aturbine 254.

The first cooling pipe 211 provides a path for supplying the treatedwater discharged from the water treatment device 20 to the heatexchanger in the data center 20. The heat exchanger of the data center20 performs cooling operation in a water cooling type by the treatedwater supplied through the first cooling pipe 211. The second coolingpipe 212 is installed outside in a shape surrounding the outer wall ofthe data center 20 or is installed to be buried in the outer wall of thedata center 20 to provide a path for supplying treated water to theoutside of the data center 20. Accordingly, heat generated from theouter wall of the data center 20 is absorbed by the treated water, sothe outer wall is cooled.

The sprinkler 213 serves to sprinkle the treated water on the outer wallor roof of the data center 20. Accordingly, the heat generated from theouter wall or roof of the data center 20 is absorbed by vaporization ofthe sprinkled treated water. In addition, the sprinkler 213 may alsoserve to supply water necessary for growth of plants using treated waterwhen there are plants planted on a roof of a building, for example, forgreening the building using plants. The sprayer 214 serves to spray thetreated water to an inlet side of the outdoor air supplied for coolingthe data center 20. Accordingly, moisture is contained in the outsideair flowing into the heat exchanger in the data center 20, and theefficiency of cooling of the data center 20 in an air cooling type isfurther increased. The treated water may be supplied to the sprinkler213 and the sprayer 214 through separate pipes branched from the coolingpipes 211 and 212.

The pump 215 supplies the treated water to the first cooling pipe 211,the second cooling pipe 212, the sprinkler 213, and the sprayer 214.Specifically, the treated water discharged from the reactor 12 issupplied to the advanced treatment device 16 to be further treated, andthe treated water discharged from the advanced treatment device 16 ispumped by the pump 215 and supplied to the first cooling pipe 211, thesecond cooling pipe 212, the sprinkler 213, and the sprayer 214.Separate valves (not illustrated) for individually controlling thesupply of treated water are installed in the first cooling pipe 211, thesecond cooling pipe 212, the sprinkler 213, and the sprayer 214, andthus, are preferably configured to selectively supply treated water tosome or all of the first cooling pipe 211, the second cooling pipe 212,the sprinkler 213, and the sprayer 214 by the pump 215. Anopening/closing operation of each valve 130 is controlled by the controlunit 400.

The recovery pipe 230 provides a path for recovering some or all of thetreated water, which is supplied to the data center 20 and used forcooling, to the water treatment device 20. Specifically, the recoverypipe 230 returns treated water discharged from the data center 20 to afront end of the reactor 12, that is, a sewage inlet through whichsewage flows into the reactor 12, and supplies the treated water to thereactor 12. Accordingly, all or some of the treated water used forcooling in the data center 20 returns to the reactor 12, and theunreturned treated water is discharged to the outside through thedischarge pipe 30. As an example, when it is necessary to increase thetemperature in the reactor 12 or the quality of the treated water isunsuitable for discharge, the treated water is recovered to the watertreatment device 20, and the treated water is discharged to the outsidewhen there is no need to increase the temperature in the reactor 12 andthe quality of the effluent meets the discharge standards.

Meanwhile, since the treated water discharged from the data center 20 isheated by the heat exchanger and has the high temperature, there is arisk of causing another environmental problem when directly dischargedto the outside. Therefore, it is preferable that most or all of thetreated water discharged from the data center 20 returns to the watertreatment device 10, and the discharge of the treated water to theoutside is made only in the water treatment device 10. Of the treatedwater discharged from the water treatment device 10, the treated waterto be discharged to the outside is discharged through the discharge pipe30.

The storage unit 251 is disposed on the treatment water movement pathbetween the water treatment device 10 and the data center 20. Thestorage unit 251 is configured as, for example, a water tank and servesto store the treated water to be supplied to the data center 20. By thestorage unit 251, the amount of treated water discharged or circulatedfrom the water treatment device 10 may be regulated in consideration ofthe amount required for cooling the data center 20.

The cooler 252 serves to cool the treated water stored in the storageunit 251. Since the treated water is cooled by the cooler 252 in a statein which the treated water is stored in the storage unit 251, when thetreated water is supplied to the data center 20, the temperature islowered, so the data center 20 may be cooled more effectively.

On the other hand, when the treated water discharged from the datacenter 20 is repeatedly used for cooling the data center 20 withoutrecovering the treated water to the water treatment device 10 ordischarging the treated water to the outside, it is preferable tocirculate the treated water. To this end, the recovery pipe 230preferably further includes a circulation pipe 231 as illustrated inFIG. 5 . The circulation pipe 231 is branched from the recovery pipe 230and provides a path for circulating the discharged water from the datacenter 20 to the storage unit 251. A valve (not illustrated) forcontrolling whether or not to supply the discharged water to thecirculation pipe 231 is installed at the point where the circulationpipe 231 is branched from the recovery pipe 230. When the valve iscontrolled so that the discharged water from the data center 20 issupplied to the circulation pipe 231, the discharged water is suppliedto the storage unit 251 and stored in the storage unit 251, and iscooled by the cooler 252 in the storage unit 251 and then reused forcooling the data center 20.

The fuel cell 253 generates electric power using biogas as a fuel. Asdescribed above, the biogas generated during the treatment bymicroorganisms in the reactor 12 is supplied to the fuel cell 253through the biogas supply pipe 150. The fuel cell 253 generateselectricity by using the biogas as a direct fuel, in which the generatedelectricity is used as a driving power supply of the cooler 252.

The turbine 254 burns the biogas to generate electric power. Asdescribed above, the biogas generated during the treatment by themicroorganisms in the reactor 12 is also supplied to the turbine 253through the biogas supply pipe 150. A burning device (not illustrated)for burning biogas is provided in the turbine 254, and the turbine 254is driven by a expansion force of hot air generated as the biogas isburned by the combustion device to generate electricity. The generatedelectricity is used as a driving power supply of the cooler 252.

Both the fuel cell 253 and the turbine 254 may be installed, or only oneof the fuel cell 253 and the turbine 254 may be installed. In addition,electricity generated by the fuel cell 253 and the turbine 254 may bestored by providing a separate storage battery.

By the fuel cell 253 and the turbine 254 configured as described above,the electric power used for the operation of the cooler 252 of the watertreatment device 20 is obtained by recycling the biogas generated in thesewage treatment process of the water treatment device 20 itself.Therefore, in the process of cooling the treated water, a separateexternal power supply is not required or the need for the external powersupply is reduced, making it possible to configure a more eco-friendlyheat exchange system.

Meanwhile, to prepare for the case where the amount of electric powergenerated by the fuel cell 253 and the turbine 254 is not sufficient byonly the biogas, the fuel cell 253 may be additionally supplied withfuel for power generation. On the other hand, when the power charged inthe fuel cell 253 exceeds the required level for the operation of thecooler 252, extra electric power may be used as power required for anoperation of various computers in the data center 20 or may be used todrive a fan for supplying external air necessary for cooling the datacenter 20.

The converter 300 converts carbon dioxide into ethanol. Carbon dioxide(CO₂) is generated while the biogas supplied to the turbine 254 isburned to drive the turbine 254, and the generated carbon dioxide mayact as a cause of global warming. Therefore, the converter 300 receivescarbon dioxide and converts the carbon dioxide into ethanol to minimizethe generation of the carbon dioxide. The ethanol generated in theconverter 300 is supplied to the reactor 12. The ethanol supplied to thereactor 12 performs a denitrification function on the sewage to betreated, and is used to increase the efficiency of the sewage treatment.

According to the present invention as described above, the heatgenerated in the external plant such as the data center 20 is used as aheat source for supplying hot air required by the water treatment device10, and the treated water of the water treatment device 10 is also usedas a coolant supply source for cooling the external plant 20.Accordingly, it is possible to supply economical hot blast through thecomplementary heat exchange between the external plant 20 and the watertreatment device 10 and also to solve the heat island phenomenon.

Meanwhile, the heat exchange system of the present invention may beoperated in an optimized manner in consideration of various factors inthe actual operation process. For example, the need for cooling the datacenter 20 in summer is greater than the need for supplying hot air tothe water treatment device 10, and vice versa in winter. Therefore, thecontrol unit 400 strengthens the circulation of the treated waterthrough the circulation pipe 231 in summer, and strengthens theoperation of the blower 120 without circulating the treated water inwinter to reduce energy costs. In addition, in the summer, it isnecessary to increase the amount of treated water supplied to the datacenter 20 and lower the temperature of the treated water, so the controlunit 400 strengthens the operation of the pump 215 and the operation ofthe cooler 252, and vice versa in winter.

In addition, the control unit 400 controls the temperature of the hotair to be lowered when the temperature of the hot air supplied to thereactor 12 through the hot-air supply unit 100 is higher than thetemperature required for the activation of microorganisms in the reactor12. Accordingly, the coolant supply unit 200 may be controlled to supplysome or all of the treated water to the hot-air pipe 110 for cooling thehot air supplied through the hot-air pipe 110. Specifically, anadditional treated water transfer pipe (not illustrated) or a spraynozzle through which the treated water discharged from the cooler 252 issprayed toward the outside of the hot-air pipe 110 is provided, and thecontrol unit 400 cools the outside of the hot-air pipe 110 by supplyingor spraying the cooled treated water to the hot-air pipe 110 through thetransfer pipe or the spray nozzle. Accordingly, the temperature of thehot air supplied to the reactor 12 may be maintained at an appropriatetemperature suitable for the activation of the microorganisms in thereactor 12.

Furthermore, the control unit 400 may control the operation of thehot-air supply unit 100 and the coolant supply unit 200 according to avalue obtained by measuring some or all of the temperature of hot air,the temperature of the reactor 12, the temperature of the data center20, the quality of the treated water, the temperature of the treatedwater, and the sewage treatment capacity of the water treatment device.Accordingly, an optimized heat exchange performance may be exhibited.

Although the present invention has been described with reference toexemplary embodiments shown in the accompanying drawings, it is only anexample. It will be understood by those skilled in the art that variousmodifications and equivalent other exemplary embodiments are possiblefrom the present invention. Accordingly, a technical scope of thepresent invention is to be defined by a technical spirit of thefollowing claims.

1. A heat exchange system between an external plant that generates heatduring operation and acts as a heat source for surrounding environmentand a water treatment device for treating sewage, the heat exchangesystem comprising: a hot-air supply unit that supplies heat generatedfrom the external plant to a reactor using microorganisms in the watertreatment device; a coolant supply unit that supplies treated waterdischarged from the water treatment device to the external plant as acoolant for heat dissipation of the external plant; and a control unitthat controls an operation of the hot-air supply unit and the coolantsupply unit.
 2. The heat exchange system of claim 1, wherein theexternal plant includes a data center that transmits and receives datathrough an external communication network and stores the data.
 3. Theheat exchange system of claim 1, wherein the hot-air supply unitincludes: a hot-air pipe that provides a hot-air movement path betweenthe reactor and a heat exchanger provided in the external plant; and ablower that blows hot air from the heat exchanger to the reactor throughthe heat engine.
 4. The heat exchange system of claim 3, wherein thehot-air pipe further provides the hot-air movement path between the heatexchanger and a dryer for drying sludge generated in the reactor, andthe blower blows hot air from the heat exchanger to the dryer throughthe hot-air pipe.
 5. The heat exchange system of claim 4, furthercomprising: a valve that is installed on the hot-air movement path ofthe hot-air pipe to control a supply of the hot air to the reactor andthe dryer through the hot-air pipe, wherein the control unit controlsthe valve so that the supply of the hot air to the reactor and the dryeris individually regulated.
 6. The heat exchange system of claim 1,wherein the coolant supply unit further includes at least one of: afirst cooling pipe that supplies the treated water to the heat exchangerprovided in the external plant; a second cooling pipe that is installedoutside the external plant or buried in an outer wall of the externalplant and supplied with the treated water; a sprinkler that cools theexternal plant by sprinkling the treated water to the outside of theexternal plant or supplies water to plants planted in the external plantfor building greening; and a sprayer that sprays the treated water tooutside air supplied for cooling the external plant.
 7. The heatexchange system of claim 6, wherein the coolant supply unit furtherincludes a pump that supplies the treated water to at least one of thefirst cooling pipe, the second cooling pipe, the sprinkler, and thesprayer.
 8. The heat exchange system of claim 1, wherein the coolantsupply unit further includes a recovery pipe that recovers some or allof the treated water, which is supplied to the external plant and usedfor cooling, to the water treatment device.
 9. The heat exchange systemof claim 1, wherein the coolant supply unit further includes a storageunit that stores the treated water to be supplied to the external plant.10. The heat exchange system of claim 9, wherein the coolant supply unitfurther includes a circulation pipe that circulates some or all of thetreated water, which is supplied to the external plant and used forcooling, to the storage unit.
 11. The heat exchange system of claim 9,wherein the coolant supply unit further includes a cooler that cools thetreated water stored in the storage unit.
 12. The heat exchange systemof claim 11, wherein the coolant supply unit further includes a fuelcell that generates electric power to be supplied to the cooler by usingbiogas generated in the reactor as a fuel.
 13. The heat exchange systemof claim 12, wherein some of the electric power output from the fuelcell is supplied to the external plant.
 14. The heat exchange system ofclaim 11, wherein the coolant supply unit further includes a turbinethat generates electric power to be supplied to the cooler by burningthe biogas generated in the reactor.
 15. The heat exchange system ofclaim 14, wherein some of the electric power output from the turbine issupplied to the external plant.
 16. The heat exchange system of claim14, further comprising: a converter that converts carbon dioxidegenerated by burning the biogas into ethanol and supplying the ethanolto the reactor.
 17. The heat exchange system of claim 1, wherein, when atemperature of the hot air supplied to the reactor through the hot-airsupply unit is higher than that required for activation of themicroorganisms in the reactor, the coolant supply unit supplies some orall of the treated water to an outside of the hot-air pipe to cool thehot air supplied through the hot-air pipe.
 18. The heat exchange systemof claim 1, wherein the control unit controls an operation of thehot-air supply unit and the coolant supply unit based on any one of atemperature of the hot air, a temperature of the reactor, a temperatureof the external plant, water quality of the treated water, a temperatureof the treated water, a sewage treatment capacity of the water treatmentdevice.